Patent Description:
A polyether polyol is an important constituent part of a polyurethane material, at present, based on continuous improvement of production technologies and devices of many manufacturers, the quality of products is also continuously improved, but the problem that the products are prone to emitting poisonous and harmful smell or gas is not well solved. With increasing attention to the environmental protection problem, consumers are also more and more critical, especially on a soft foam polyether polyol applied to furniture, automobiles, clothes and the like which are directly related to daily life of people, so that the demand of a low-odor polyether polyol grows increasingly.

The odor of a polyether polyol comes from several of the following substances:.

Thus it can be seen that toxic and harmful gases are generated and a lot of odors are volatilized no matter in the polyether polyol production process or in the refining process, however, many manufacturers only focus on odor removal in the refining process, although a certain effect is achieved, it does not work from the source, and problems of long treatment time and impaired yield exist. For example, Chinese patent <CIT> discloses that a hydrazine compound is added to a crude polyether polyol as an aldehyde catching agent in a refining process, and reacts with aldehyde substances in inert gas at a certain temperature to achieve the purpose of removing the aldehyde substances, so that the odor of the product is reduced. The patent <CIT> discloses a refining method of a low-odor polyether polyol and application thereof, a compound antioxidant is added in the refining process, the influence of the antioxidant on the odor of a product is reduced, the purpose of reducing the odor is achieved, and reduction of odor from the source is not considered in the above description.

Therefore, a preparation method of a low-odor polyether polyol was disclosed in the patent <CIT> of Sinopec, in the preparation method, low-aldehyde propylene oxide is utilized to produce the low-odor polyether polyol, and the specific method includes: enabling the propylene oxide to pass through a molecular sieve tank at an air speed of <NUM>-<NUM>, and carrying out aldehyde reduction treatment through the molecular sieve tank to obtain low-aldehyde propylene oxide, and producing the low-odor polyether polyol by using low-aldehyde propylene oxide. Although this method can reduce the generation of odor from the source, the technological process is complicated, the treatment time is long, and the yield is seriously damaged. <CIT> describes a polyether polyol refining method, comprising (<NUM>) neutralising or diluting crude polyether polyol to obtain a mixed solution; (<NUM>) flowing the mixed solution through a hydrophilic medium to aggregate same into a first density phase liquid and a second density phase liquid, the first density phase liquid being an aqueous solution containing alkaline metal ions and/or alkaline earth metal ions, and the second density phase liquid being polyether polyol; and (<NUM>) allowing the first density phase liquid to settle and separating same from the second density phase liquid to obtain refined polyether polyol. Also described is a polyether polyol refining apparatus, comprising a mixing unit and a separating unit.

Therefore, the technical problem to be solved by the present disclosure is to overcome the defects that the treatment time is long and the yield is seriously damaged when a low-odor polyether polyol is prepared by adopting a method in the prior art, and meanwhile, the odor of the polyether polyol is further reduced, so that a process and system for producing a low-odor polyether polyol are provided.

The present disclosure provides a process for producing a low-odor polyether polyol, including the following steps:.

Further, in the circulation distribution polymerization step, the ratio of the flow rate of the mixed material sprayed into the reaction container to the volume of the reaction container is <NUM>-<NUM> tons/hour: <NUM> cubic meter.

Preferably, in the initial polymerization reaction step and the circulation distribution polymerization step, the ratio of the flow rate of the epoxy olefin input into the reaction container to the volume of a reactor is <NUM>-<NUM> ton/hour: <NUM> cubic meter; and
the epoxy olefin is one or a mixture of at least two of ethylene oxide, propylene oxide and butylene oxide.

Further, in the initial polymerization reaction step and/or the circulation distribution polymerization step, a temperature of the polymerization reaction is controlled to be <NUM>-<NUM>.

The present disclosure further provides a system for producing a low-odor polyether polyol, including:.

Further, the circulation distributor is of a spiral structure or a parallel annular structure.

Preferably, the circulation distributor further includes:
a plurality of diversion ports, wherein the circulation distributor communicates with atomizers or nozzles by means of the diversion ports.

Further, the spiral circulation distributor includes <NUM>-<NUM> spiral rings or annular rings in a vertical direction.

Preferably, the circulation distributor is located at one end close to the bottom or top of the reactor.

Further, the production process applies the production system according to any one of claims <NUM>-<NUM>.

The technical solution of the present disclosure has the following advantages:
according to the process for producing the low-odor polyether polyol provided by the present disclosure, the initial polymerization reaction step, the circulation distribution polymerization step and the refining step are sequentially carried out, and the three processes exert a synergistic effect, so that the diffusion rate of the mixed material is greatly increased, the mixing uniformity is improved, the reaction rate is increased, the generation of impurities is reduced, and the generation of odor is reduced; moreover, in the circulation distribution polymerization step, through outputting, splitting and spraying, the operations are circulated, the ratio of the flow rate of the mixed material sprayed into the reaction container to the volume of the reactor is <NUM>-<NUM> tons/hour: <NUM> cubic meter, and the mixed material sprayed into the reaction container is stirred by maintaining the rotating speed of <NUM>-<NUM> r/min, so that the forward progress of the reaction is greatly improved, side reactions are reduced, and a crude polyether polyol with low VOC content is prepared; in combination with the refining step, namely, the crude polyether polyol is taken and subjected to neutralization or dilution treatment to obtain the mixed solution of the crude polyether polyol, then the mixed solution flows through the hydrophilic medium to be aggregated, settled and separated to obtain the low-odor polyether polyol, and the process for producing the low-odor polyether polyol has the advantages of short treatment time, high yield and low VOC content.

In order to more clearly illustrate the specific embodiments of the present disclosure or the technical solutions in the prior art, the drawings used in the specific embodiments or descriptions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present disclosure, and other drawings can be obtained by those of ordinary skill in the art according to these drawings without creative efforts.

<NUM>-mixing unit; <NUM>-first fluid sample inlet; <NUM>-second fluid sample inlet; <NUM>-mixing inner cavity; <NUM>-sample outlet; <NUM>-separation unit; <NUM>-mixed solution inlet; <NUM>-second density phase outlet; <NUM>-first density phase outlet; <NUM>-separation inner cavity; <NUM>-sample inlet assembly; <NUM>-separation assembly; <NUM>-pressurizing unit; <NUM>-pipeline; <NUM>-reaction container; <NUM>-epoxy olefin feeding port; <NUM>-discharging port; <NUM>-stirrer; <NUM>-circulation pump; and <NUM>-circulation distributor.

This embodiment provides a system for producing a low-odor polyether polyol, as shown in <FIG> and <FIG>, the system includes a reaction container <NUM>, a circulation distributor <NUM> and a refining system, the reaction container <NUM> is provided with a catalyst feeding port, an initiator feeding port, an epoxy olefin feeding port <NUM> and a discharging port <NUM> used for moving a mixed material out of the reaction container, and a stirrer <NUM> is arranged in the reaction container <NUM>; the circulation distributor <NUM> is located in the reaction container <NUM>, the circulation distributor <NUM> is provided with a plurality of outlets, the outlets of the circulation distributor <NUM> communicate with an inner cavity of the reaction container, and an inlet of the circulation distributor <NUM> communicates with the discharging port of the reaction container <NUM> by means of a circulation pump <NUM>; and as shown in <FIG>, the circulation pump <NUM> in the embodiment is provided with one inlet and two outlets, the inlet of the circulation pump <NUM> communicates with the discharging port of the reaction container <NUM> through a conveying pipe, one of the outlets extends into the reaction container <NUM> through a conveying pipe and communicates with the inlet of the circulation distributor <NUM>, the other outlet communicates with the refining system through a conveying pipe, and the conveying pipe is provided with a valve control switch.

The circulation distributor <NUM> is of a spiral structure, a parallel annular structure or other structures (as shown in <FIG> and <FIG>), the circulation distributor <NUM> further includes: a plurality of diversion ports, and the circulation distributor <NUM> communicates with atomizers or nozzles by means of the diversion ports; and the circulation distributor <NUM> includes <NUM>-<NUM> spiral rings or annular rings in a vertical direction. The circulation distributor <NUM> is located at the end, close to the bottom or the top, of a reactor.

During use, a valve on the conveying pipe between the circulation pump <NUM> and the circulation distributor <NUM> is opened, a valve on the conveying pipe between the circulation pump <NUM> and the refining system is closed, the circulation pump <NUM> is started, a material in the reaction container <NUM> is conveyed to the circulation distributor <NUM> through the discharging port <NUM> via the circulation pump <NUM>, is sprayed out through the nozzles at the diversion ports of the circulation distributor <NUM>, is sprayed into the reaction container <NUM>, and is output through the circulation pump <NUM> via the discharging port <NUM> at the bottom of the reaction container <NUM> to achieve circulation.

The refining system includes a mixing unit <NUM>, a pressurizing unit <NUM> and a separation unit <NUM>. The pressurizing unit <NUM> is located on a pipeline <NUM> for communicating the mixing unit <NUM> with the separation unit <NUM>.

The mixing unit <NUM> is provided with a mixing inner cavity <NUM> as well as two sample inlets and one sample outlet <NUM> which communicate the mixing inner cavity <NUM> with the outside. As shown in <FIG>, the mixing unit <NUM> is a neutralization reactor, the two sample inlets are a first fluid sample inlet <NUM> formed in the vertical side wall face of the neutralization reactor and a second fluid sample inlet <NUM> formed in the top wall face of the neutralization reactor, and the sample outlet <NUM> is formed in the bottom wall face of the neutralization reactor.

The sample outlet <NUM> of the mixing unit <NUM> communicates with the pressurizing unit <NUM>, such as a pressurizing pump, through the pipeline <NUM>. The pressurizing pump is provided with an input end and an output end, the pipeline <NUM> penetrates out from the output end after penetrating into the pressurizing pump from the input end. The pipeline <NUM> close to the input end communicates with the mixing unit <NUM>, and the pipeline <NUM> close to the output end communicates with the separation unit <NUM>. The pressurizing pump is mounted on the pipeline <NUM>, pressure of liquid in the pipeline <NUM> can be increased, and thus, a mixed solution is delivered from the mixing unit <NUM> to the separation unit <NUM>.

The separation unit <NUM> includes a desalter communicating with the sample outlet <NUM> of the mixing unit <NUM>, the desalter is provided with a separation inner cavity <NUM>, a first density phase outlet <NUM>, a second density phase outlet <NUM> and a mixed solution inlet <NUM>, wherein the first density phase outlet <NUM> and the second density phase outlet <NUM> communicate the separation inner cavity <NUM> with the outside, and the mixing solution inlet <NUM> keeps away from the first density phase outlet <NUM> and the second density phase outlet <NUM>. As shown in <FIG>, the mixed solution inlet <NUM> is formed in the vertical side wall face of the desalter, the first density phase outlet <NUM> is formed in the bottom wall face of the desalter, and the second density phase outlet is formed in the top wall face of the desalter. The pipeline <NUM> communicating the neutralization reactor with the desalter penetrates out from the output end of the pressurizing pump, and then is connected to the mixed solution inlet <NUM> of the desalter.

A sample inlet assembly <NUM> and a separation assembly <NUM> are arranged in the separation inner cavity <NUM>, the sample inlet assembly <NUM> is connected with the mixed solution inlet <NUM> and the separation assembly <NUM>, as shown in <FIG>, the separation assembly <NUM> includes four separation pieces arranged in parallel, and the separation pieces are tubular, and extend in the circulating direction of the mixed solution; one end of the sample inlet assembly <NUM> is connected with the four separation pieces, the other end of the sample inlet assembly <NUM> is connected with the mixed solution inlet <NUM>, four sample inlet tubes which are in one-to-one correspondence to the separation pieces are arranged in the sample inlet assembly <NUM>, one ends of the sample inlet tubes are connected with the tubular separation pieces, and the ends, away from the separation pieces, of the sample inlet tubes are connected with the mixed solution inlet <NUM>. The mixed solution flowing in from the mixed solution inlet <NUM> flows into the sample inlet assembly <NUM> firstly, is uniformly split into various diversion tubes, and then correspondingly flows into the various separation pieces. By the sample inlet assembly <NUM>, the mixed solution can flow into the various separation pieces of the separation assembly <NUM> in an equal amount.

Each separation piece of the separation assembly <NUM> is provided with a circulating cavity for circulating the mixed solution, and each circulating cavity is filled with a hydrophilic medium which is formed by glass fibers containing at least one group of hydroxyl, acylamino, amino and carboxyl, or formed by fibers of polymers, or formed by mixing the glass fibers with the fibers of polymers. For example, the hydrophilic medium is glass fibers connected with hydroxyl. The hydrophilic medium is rich in polar group, and has high adsorption affinity to water.

In the embodiment, when the refining system is used for refining the polyether polyol, an acid solution, such as a phosphoric acid solution, is introduced into the neutralization reactor through the first fluid sample inlet <NUM> formed in the neutralization reactor, and a crude polyether polyol is introduced into the neutralization reactor through the second fluid sample inlet <NUM> formed in the neutralization reactor. In the mixing inner cavity <NUM> of the neutralization reactor, the acid solution and the crude polyether polyol are stirred and uniformly mixed, the crude polyether polyol is subjected to neutralization treatment, a catalyst remaining in the crude polyether polyol is dissolved in water in a form of alkaline metal or alkaline-earth metal ions, and is dispersed in the polyether polyol in a form of liquid drops, so that a mixed solution containing the crude polyether polyol is obtained.

Then, the mixed solution flows out through the sample outlet <NUM> in the bottom of the neutralization reactor and flows to the desalter through the connecting pipeline <NUM>. When flowing through the pressurizing pump, the mixed solution penetrates through the input end of the pressurizing pump in the pipeline <NUM> and then penetrates out of the output end, and the pressurizing pump pressurizes the liquid in the pipeline <NUM>, so that the mixed solution is continuously delivered to the desalter after flowing through the pressurizing pump.

The mixed solution is delivered to the desalter through the pipeline <NUM> and flows into the separation inner cavity <NUM> of the desalter through the mixed solution inlet <NUM> formed in the vertical side wall face of the desalter. In the separation inner cavity <NUM>, the mixed solution firstly flows into the sample inlet tubes of the sample inlet assembly <NUM> to be split, and then flows into the separation pieces communicating with the sample inlet tubes in a one-to-one correspondence manner through the sample inlet tubes in an equal amount. The mixed solution flows through the hydrophilic medium in the process of circulating in the circulating cavities of the separation pieces, and due to hydrophilicity of the hydrophilic medium, the polyether polyol in the mixed solution flows out first after flowing through the hydrophilic medium and is gathered into second density phase liquid; water phase liquid drops in the mixed solution are adsorbed on the surface of the hydrophilic medium after being in contact with the hydrophilic medium, the water phase liquid drops are continuously gathered on the surface of the hydrophilic medium along with circulating of the mixed solution, and after reaching a certain volume, the water phase liquid drops are separated from the hydrophilic medium under the action of gravity and are gathered to form first density phase liquid.

Because alkaline metal ions and/or alkaline-earth metal ions are dissolved in the first density phase liquid, the density of the first density phase liquid is greater than that of the second density phase liquid, after settling for a period of time, the first density phase liquid is gathered to a position below the second density phase liquid, and flows out of the separation inner cavity <NUM> through the first density phase outlet <NUM> formed in the bottom wall face of the desalter; and the density of the second density phase liquid is smaller, and flows out of the separation inner cavity <NUM> via the second density phase outlet <NUM> formed in the top wall face of the desalter, and meanwhile, alkaline metal ions, alkaline-earth metal ions and water in the polyether polyol are removed to obtain the refined polyether polyol.

By the refining system, catalyst metal ions and water which remain in the polyether polyol can be removed simultaneously, the step of refining the polyether polyol is simplified, and the refining efficiency of the polyether polyol is improved. The content, less than or equal to <NUM> ppm, of total aldehyde in the obtained polyether polyol is low, odor is small, and environmental friendliness is high. Alkaline metal ions in the polyether polyol are effectively removed, the polyether polyol can be directly used for synthesizing a polyurethane product, side reactions in a synthesizing process of the polyurethane product can be reduced, and the quality of the synthesized polyurethane product is improved.

This embodiment provides a process for producing a low-odor polyether polyol, including the following steps:.

According to the relevant regulations of the national standard GB/T37196-<NUM>, the content of total aldehyde of the refined polyether polyol is measured, and the measured results include that the content of total aldehyde is <NUM> ppm, wherein the content of formaldehyde is <NUM> ppm, the content of acetaldehyde is ND, the content of acrolein is ND, and the odor grade of the product is identified as grade <NUM>.

According to the relevant regulations of the national standard GB/T37196-<NUM>, the content of total aldehyde of the refined polyether polyol is measured, and the measured results include that the content of total aldehyde is <NUM> ppm, wherein the content of formaldehyde is <NUM> ppm, the content of acetaldehyde is ND, the content of acrolein is ND and the odor grade of the product is identified as grade <NUM>.

This comparative example provides a process for producing a low-odor polyether polyol, including the following steps:.

According to the relevant regulations of the national standard GB/T37196-<NUM>, the content of aldehyde of the refined polyether polyol is measured, and the measured results include that the content of formaldehyde is <NUM> ppm, the content of acetaldehyde is <NUM> ppm, and the content of acrolein is ND; and the odor grade of the product is identified as grade <NUM>.

According to the relevant regulations of the national standard GB/T37196-<NUM>, the content of total aldehyde of the refined polyether polyol is measured, and the measured results include that the content of total aldehyde is <NUM> ppm, wherein the content of formaldehyde is <NUM> ppm, the content of acetaldehyde is <NUM> ppm, the content of acrolein is ND, and the odor grade of the product is identified as grade <NUM>.

Claim 1:
A process for producing a low-odor polyether polyol, characterized by comprising the following steps:
an initial polymerization reaction step, comprising: adding an initiator and an alkaline catalyst into a reaction container, and then inputting an epoxy olefin into the reaction container for a polymerization reaction to obtain a mixed material;
a circulation distribution polymerization step, comprising: taking the mixed material for outputting, splitting and spraying into the reaction container at a high speed, followed by circulating the above operations while inputting the epoxy olefin and maintaining a rotation speed of <NUM>-<NUM> r/min for stirring the mixed material that has been sprayed into the reaction container, continuing to proceed with the polymerization reaction, and curing to obtain a crude polyether polyol; and
a refining step, comprising: taking the crude polyether polyol for a neutralization or dilution treatment to obtain a mixed solution of the crude polyether polyol, then aggregating a mixed solution stream by means of a hydrophilic medium, settling and separating to obtain the low-odor polyether polyol;
wherein in the circulation distribution polymerization step, a ratio of a flow rate of the mixed material sprayed into the reaction container to a volume of the reaction container is <NUM>-<NUM> tons/hour: <NUM> cubic meter.