JP2005218960A - Sulfate pitch treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the handleability of sulfate pitch even when the pitch is one illegally discarded and is then solidified. <P>SOLUTION: The sulfate pitch treatment method comprises fluidizing sulfate pitch solidified in a container such as a drum by heating it at a temperature which varies from 40°C to below 200°C dependent on its sulfate ion concentration and withdrawing the fluidized pitch from the container. The heated and fluidized sulfate pitch can flow out from the exit of a container, e.g., a drum and can therefore be easily discharged from the container. The fluidized sulfate pitch discharged from the container can be solidified into a desired form by cooling it in e.g., a mold. The thus solidified sulfate pitch in the desired form is excellent in handleability and can be treated by incineration in e.g., an incinerator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for treating sulfuric acid pitch generated by sulfuric acid washing of petroleum products.

  In sulfuric acid cleaning performed to refine petroleum products, sulfuric acid pitch is generated. Such sulfuric acid pitch emits harmful gases and produces bad odors, which need to be rendered harmless. The hardness of sulfuric acid pitch varies from gum-like, caramel-like, and bowl-like. On the other hand, although sulfuric acid pitch has some fluidity (for example, about 10 P) when it is generated, it has a property of gradually hardening with the passage of time. Since sulfuric acid pitch contains sulfuric acid, etc., it is stored and transported and stored in a sealable container such as a drum can until it is processed. The resulting sulfuric acid pitch is not fluid and cannot be easily removed from the drum. For this reason, there exists a difficulty that the handleability at the time of processing a sulfuric acid pitch is inferior.

  Recently, sulfuric acid pitch packed in drums has been illegally dumped in Yamano, and the problem of contaminating the surrounding environment due to sulfuric acid pitch leaking from corroded drums has become apparent. Such illegally dumped sulfuric acid pitch often passes for a long time until discovery, and the drum can corrodes and breaks down, and the liquid flows out and only the solid content remains, or the drum can over time. In many cases, the sulfuric acid pitch hardens and loses fluidity, resulting in poor handling. Since sulfuric acid pitch hardens even in the state of being stored in a container, it was not possible to extract the sulfuric acid pitch from the drum, and measures such as incineration or pulverization of the entire container were taken. This is because the sulfuric acid pitch has a large component variation, the amount of heat is difficult to predict, the furnace temperature rises more than expected, and it contains a strong acid, which may damage the furnace wall. ， Secondary contamination of equipment is also considered and its practicality is poor. For this reason, the invention of the method of extracting sulfuric acid pitch simply from airtight containers like a drum can was desired.

  In addition, since sulfuric acid pitch is a deleterious substance, it must be handled with great care. Since the viscosity of sulfuric acid pitch changes with temperature, naturally, the temperature resistance, chemical resistance at operating temperature, and maintainability of equipment that handles sulfuric acid pitch must be taken into consideration. When the processing temperature of sulfuric acid pitch is set to a certain level, it is desirable that the properties (viscosity) of the liquid do not change greatly. The sulfuric acid pitch is stored in a semi-indoor area where the space is limited and the temperature is not controlled at the storage area. In winter, even if it is heated once due to the influence of outside air temperature, it will solidify after a few minutes if heating is stopped. Large heating devices are not preferred because of space, and temperature control is not so accurate due to the influence of outside air temperature.

  Therefore, in order to fluidize the sulfuric acid pitch, Japanese Patent Laid-Open No. 53-2958 discloses that the sulfuric acid pitch of solid content is heated to 60-80 ° C. using the exhaust heat of the incinerator and liquefied. It is disclosed. Japanese Laid-Open Patent Publication No. 2002-1399 discloses a method of mixing a sulfuric acid pitch with a solubilizing agent such as fuming sulfuric acid and waste sulfuric acid, and dissolving a solid content in the sulfuric acid pitch to perform a roasting treatment. On the other hand, Japanese Patent Application Laid-Open No. 50-70420 discloses a method of heating to 200 to 400 ° C. while mixing sulfuric acid pitch to obtain a powdery polymer.

Japanese Patent Laid-Open No. 53-2958 JP 2002-1399 A JP-A-50-70420

  Sulfuric acid pitch is finally incinerated, but fluidized sulfuric acid pitch is inferior in handleability and is difficult to supply to an incinerator. For example, even if an attempt is made to spray sulfuric acid pitch liquefied by heating from an nozzle to an incinerator or the like, clogging will occur immediately, making it impossible to supply. In addition, the fluidized sulfuric acid pitch is mud, so it is inconvenient to put into an incinerator, etc., and there is a concern that the adhesion will be high and the surroundings will be soiled.

  In addition, the method of dissolving sulfuric acid pitch using sulfuric acid generates a large amount of sulfurous acid gas at the time of dissolution, which necessitates a highly sealed neutralization facility or gas treatment facility. In addition, when sulfuric acid pitch is dissolved with sulfuric acid, a large amount of strongly acidic sludge that is difficult to treat is produced.

  On the other hand, in order to perform heat treatment while mixing sulfuric acid pitch, it is necessary to mix in a heating furnace or the like, but it is impossible to mix sulfuric acid pitch hardened in a drum can. Sulfuric acid pitch contains a complex mixture of organic substances such as tar, sulfuric acid, and oil, so various processing methods can be used. Therefore, the treatment method must be examined according to the situation and the like, and there has been a demand for a method that can reliably and easily perform the treatment.

  An object of the present invention is to allow a hardened sulfuric acid pitch such as illegal dumping to be taken out from a container such as a drum can in a safe and stable state, and to be put into incineration processing or pretreatment before incineration. .

When the cured sulfuric acid pitch is heated in a certain temperature range, the fluidity is most excellent, and the temperature range showing such fluidity is the sulfate ion concentration of the sulfuric acid pitch. And found that there is a close relationship. Based on this knowledge, according to the present invention, the sulfuric acid pitch hardened in the container is heated at a temperature of 40 ° C. or more and less than 200 ° C. according to the sulfate ion concentration (SO ₄ ^2- ion concentration). A method for treating sulfuric acid pitch is provided, characterized in that the sulfuric acid pitch that has been converted into fluid and fluidized is taken out of the vessel. In the present application, the “cured sulfuric acid pitch” means that the sulfuric acid pitch placed in a container such as a steel can is in a state in which the opening of the container is directed downward, as will be described later in the examples. (For example, 5 minutes) This refers to a state where it cannot be washed away even after elapses.

  For example, a sulfuric acid pitch having a sulfate ion concentration exceeding 25 wt% is heated at a temperature of 40 ° C. or higher and lower than 200 ° C. In addition, sulfuric acid pitch having a sulfate ion concentration exceeding 10 wt% is heated at a temperature exceeding 80 ° C. and less than 200 ° C. In addition, sulfuric acid pitch having a sulfate ion concentration of 10 wt% or less is heated at a temperature exceeding 100 ° C. and less than 200 ° C.

  According to the present invention, the sulfuric acid pitch hardened in the container is fluidized by heating at a temperature exceeding 100 and less than 200 ° C., and the fluidized sulfuric acid pitch is taken out from the container. A method for treating sulfuric acid pitch is provided.

  Heating can be performed using, for example, a drum heater, a heating furnace, or a hot water bath. The sulfuric acid pitch taken out from the container may be cooled and solidified in a desired form. In that case, the sulfuric acid pitch cooled and solidified in the desired form may be put into an incinerator and incinerated. The container is, for example, a drum can.

  According to the present invention, sulfuric acid pitch hardened in a drum can or the like can be fluidized by heating to a predetermined temperature. In this case, the heating energy cost and the heat treatment time can be reduced by changing the heating temperature of the sulfuric acid pitch in accordance with the concentration of sulfate ions contained in the sulfuric acid pitch and keeping the heating temperature as low as possible. The fluidized sulfuric acid pitch can be discharged from, for example, a drum can outlet and can be easily taken out from the drum. Then, the fluidized sulfuric acid pitch taken out from the drum can etc. can be solidified in a desired form, for example, by cooling in a mold. The sulfuric acid pitch thus cooled and solidified in a desired form is excellent in handleability, and can be put into an incinerator and incinerated, for example. In this case, the sulfuric acid pitch may be incinerated with the soil.

Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 is a flowchart for explaining a processing method according to an embodiment of the present invention. As shown in FIG. 1, the processing method according to the embodiment of the present invention includes the following steps (1) to (3).
(1) Step of heating sulfuric acid pitch (2) Step of cooling sulfuric acid pitch (3) Step of incinerating sulfuric acid pitch Hereinafter, each of these steps will be described.

(1) A step of heating the sulfuric acid pitch.
First, the sulfuric acid pitch hardened in a container such as a drum can is heated to a predetermined temperature range by, for example, using a drum heater or a special firing furnace. Sulfuric acid pitch is generated by sulfuric acid cleaning performed in the refining of petroleum products such as gasoline, kerosene, light oil, heavy oil, and lubricating oil, or in the production of reclaimed oil. Tar oil, sulfur content in petroleum products, asphalt , Contains gum-like substances, various sulfonic acids, sulfuric acid, etc., and produces harmful sulfurous acid gas. The properties of the sulfuric acid pitch are various, such as gum, caramel, and bowl-like, but in the present invention, the sulfuric acid pitch that does not flow and is hardened especially in the container over time. Is targeted.

  The sulfuric acid pitch can be heated to a temperature range of 40 ° C. or higher and lower than 200 ° C. depending on the sulfate ion concentration. That is, first, the sulfate ion concentration of the sulfuric acid pitch is measured, and the sulfuric acid pitch is fluidized by heating to a predetermined temperature according to the sulfate ion concentration. In this case, for example, if the sulfuric acid pitch is higher than 25 wt%, the sulfuric acid pitch can be fluidized by heating at a temperature of 40 ° C. or higher and lower than 200 ° C. Further, if the sulfuric acid pitch has a sulfate ion concentration exceeding 10 wt%, the sulfuric acid pitch can be fluidized by heating at a temperature exceeding 80 ° C. and less than 200 ° C. If the sulfuric acid pitch is 10 wt% or less, the sulfuric acid pitch can be fluidized by heating at a temperature exceeding 100 ° C. and below 200 ° C.

  On the other hand, when it is desired to omit the measurement of the sulfate ion concentration, such as when the sulfate ion concentration of the sulfuric acid pitch cannot be measured, the sulfuric acid pitch may be heated at a temperature exceeding 100 ° C. and less than 200 ° C. If heated to this temperature range, any concentration of sulfuric acid pitch can be fluidized.

  The sulfuric acid pitch may be heated in the atmosphere, but may be heated in an inert atmosphere such as nitrogen gas or argon gas. In particular, when heating at high temperatures, ignition can be prevented by heating in an inert atmosphere. The fluidized sulfuric acid pitch can be discharged from, for example, a drum can outlet and can be easily taken out from the container.

(2) A step of cooling the sulfuric acid pitch.
Next, the sulfuric acid pitch taken out from a container such as a drum can is cooled and solidified in a desired form. Cooling can be performed by air cooling or the like.

  In this case, the still fluid sulfuric acid pitch taken out from the container is placed in a mold and then solidified by cooling. Thereby, the sulfuric acid pitch can be cooled and solidified to a desired shape and size.

(3) A step of incinerating sulfuric acid pitch.
The sulfuric acid pitch cooled and solidified to a desired form can be put into, for example, an incinerator and incinerated. In this case, the shape and size are easy to handle, so it can be easily put into an incinerator through a side hopper. Further, for example, the sulfuric acid pitch cooled and solidified in a desired form may be blended with other processed materials such as industrial waste and then put into an incinerator or the like to be incinerated.

  The sulfuric acid pitch that has been cooled and solidified to the desired form is dissolved in, for example, a polar organic solvent such as an aqueous solution of NaOH or KOH, or an alcohol, and sprayed as a solution or slurry onto an incinerator for incineration. May be.

The sulfuric acid pitch was heated together with the container, and the temperature and viscosity were investigated. The cured sulfuric acid pitch was heated in a cylindrical container (steel can), and the state change was investigated. FIG. 2 shows the relationship between temperature and viscosity for sulfuric acid pitch having a sulfate ion concentration (SO ₄ ^2- ion concentration) of 25 wt%. In the case of sulfuric acid pitch with a sulfate ion concentration of 25 wt%, solidification progressed by oxidation reaction during heating from room temperature to about 70 ° C, but after that, it gradually softens with increasing temperature and exceeds 80 ° C to 200 ° C. In the temperature range below, the viscosity of sulfuric acid pitch was the lowest and showed a stable flow state. In particular, at 120 ° C. or higher, softening progressed due to the boiling of water contained in the sulfuric acid pitch, and a good flow state was shown. However, when the temperature exceeded 200 ° C., the water content decreased and it was cured again. In the temperature range above 80 ° C. and below 200 ° C., even if the temperature fluctuates (for example, even if the temperature fluctuates at about 20 ° C. from +10 to −10 ° C.), there is little change in viscosity, The range of selection of equipment that handles pitch is widened and handling is easy. Thus, it is not clear why the change in viscosity is small over a wide range of about 120 ° C. between 80 ° C. and less than 200 ° C., but with many components contained in sulfuric acid pitch, It seems that the change occurs, and as a result, the change in the viscosity is suppressed in the temperature range of more than 80 ° C. and less than 200 ° C. At 80 ° C or lower, the viscosity of sulfuric acid pitch decreases as the temperature increases. However, since the viscosity changes greatly depending on the temperature, considerable care must be taken in temperature management, and it is not accurately controlled in a fairly narrow temperature range. As a result, clogging occurs in the liquid supply pipe, etc., and adverse effects on the handling equipment are expected. At 200 ° C. or higher, the viscosity increases rapidly due to the effect of vaporization, etc., so it is more rational to solidify and pulverize and take out from the container than to remove it from the liquid. The sulfuric acid pitch fluidized by heating solidifies as soon as it is air-cooled, making it difficult to pump up.

Next, the relationship between temperature and viscosity was investigated for each sulfuric acid pitch having a sulfate ion concentration (SO ₄ ²⁻ ion concentration) of 10 wt%, 25 wt%, and 40 wt%. 280 g of sulfuric acid pitch with sulfate ion concentration of 10 wt%, 25 wt%, and 40 wt% is put into a φ60mm cylindrical container, respectively, and heated to 40 ° C, 80 ° C, 100 ° C, 120 ° C, 160 ° C, and 200 ° C, respectively. The time required to drain the entire volume from the container was measured. Outflow from the inside of the container was performed with the opening of the container facing down. As a result, less than 1 minute was judged as ○, 1 minute or more, less than 5 minutes as Δ, and 5 minutes or more as ×. The sulfuric acid pitch having a sulfate ion concentration of 10 wt% showed fluidity from around 100 ° C., and 160 ° C. was good. The sulfuric acid pitch with a sulfate ion concentration of 25 wt% showed fluidity from around 80 ° C., and 160 ° C. was good. The sulfuric acid pitch with a sulfate ion concentration of 40 wt% had good fluidity in the range of 40 ° C. to 160 ° C. However, any sulfuric acid pitch with sulfate ion concentrations of 10 wt%, 25 wt%, and 40 wt% had poor fluidity at 200 ° C. Thus, the sulfuric acid pitch was fluidized by heating to a predetermined temperature according to the sulfate ion concentration of the sulfuric acid pitch, and was able to flow out from the container. In particular, in the temperature range exceeding 100 ° C. and less than 200 ° C., any concentration of sulfuric acid pitch showed fluidity. When it is desired to omit the measurement of the sulfate ion concentration, for example, when the sulfate ion concentration of the sulfuric acid pitch cannot be measured, the heating may be performed in a temperature range exceeding 100 ° C. and less than 200 ° C.

  The present invention is used particularly for the treatment of sulfuric acid pitch whose handling property has deteriorated due to solidification after a long period of time such as illegal dumping.

It is a flowchart for demonstrating the processing method concerning embodiment of this invention. It is a graph which shows the relationship between the temperature at the time of heating the solidified sulfuric acid pitch (sulfate ion concentration of 25 wt%), and a viscosity.

Claims (8)

The sulfuric acid pitch cured in the container is fluidized by heating at a temperature of 40 ° C. or more and less than 200 ° C. according to the sulfate ion concentration, and the fluidized sulfuric acid pitch is taken out from the container. Pitch processing method. The method for treating a sulfuric acid pitch according to claim 1, wherein the sulfuric acid pitch having a sulfate ion concentration exceeding 25 wt% is heated at a temperature of 40 ° C or higher and lower than 200 ° C. The method for treating a sulfuric acid pitch according to claim 1, wherein the sulfuric acid pitch having a sulfate ion concentration exceeding 10 wt% is heated at a temperature exceeding 80 ° C and less than 200 ° C. The method for treating a sulfuric acid pitch according to claim 1, wherein the sulfuric acid pitch having a sulfate ion concentration of 10 wt% or less is heated at a temperature exceeding 100 ° C and lower than 200 ° C. A method for treating sulfuric acid pitch, characterized in that sulfuric acid pitch cured in a container is heated and fluidized at a temperature exceeding 100 and less than 200 ° C., and the fluidized sulfuric acid pitch is taken out from the container. The sulfuric acid pitch processing method according to claim 1, 2, 3, 4, or 5, wherein the sulfuric acid pitch taken out from the container is cooled and solidified in a desired form. The sulfuric acid pitch processing method according to claim 6, wherein the sulfuric acid pitch cooled and solidified in the desired form is put into an incinerator and incinerated. The method for treating a sulfuric acid pitch according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the container is a drum.

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