Method for vapor phase catalytic oxidation

1. A method for vapor phase catalytic oxidation for obtaining a reaction product gas by using a fixed bed multi-tube heat-exchanger type reactor provided with a plurality of reaction tubes and by feeding a raw material gas inside the reaction tubes packed with a catalyst while leaving an empty portion in the upper portion of the reaction tubes, wherein the method comprises:

adjusting pressure losses of the respective reaction tubes so that the pressure losses of the respective reaction tubes after catalyst packing is within ±20% of an average pressure loss of the reaction tubes by: packing an inert substance into the empty portion at a raw material gas inlet portion of the reaction tubes or removing and re-packing the catalyst packed, for a reaction tube having a pressure loss lower than the average pressure loss of the reaction tubes; and removing and re-packing the catalyst packed, for a reaction tube having a pressure loss higher than the average pressure loss of the reaction tubes.

2. The method for vapor phase catalytic oxidation according to claim 1 , wherein the inert substance for adjusting pressure loss is at least one substance selected from the group consisting of alumina, silicon carbide, silica, zirconium oxide, and titanium oxide.

3. The method for vapor phase catalytic oxidation according to claim 1 , wherein a shape of the inert substance for adjusting pressure loss is spherical, cylindrical, ring-shaped, or amorphous.

4. The method for vapor phase catalytic oxidation according to claim 1 , wherein the catalyst is an Mo—Bi mixed oxide catalyst or an Mo—V mixed oxide catalyst.

5. The method for vapor phase catalytic oxidation according to claim 1 , wherein a shape of the catalyst is spherical, cylindrical, ring-shaped, or amorphous.

6. The method for vapor phase catalytic oxidation according to claim 1 , wherein the catalyst is a single catalyst or a catalyst diluted with the inert substance.

7. The method for vapor phase catalytic oxidation according to claim 1 , wherein the method further comprises:

predicting reaction states inside the reaction tubes through measurement of catalyst layer temperature of the reaction tubes or through simulation analysis of a fluid state of a heating medium circulating outside the reaction tubes with heat of reaction inside the reaction tubes using a computer; and

determining catalyst packing specifications of the reaction tubes according to the prediction results so that nonuniformity of the reaction states among the reaction tubes are reduced for packing the catalyst in the reaction tubes.

8. The method for vapor phase catalytic oxidation according to claim 7 , wherein items determining the catalyst packing specifications include items of a catalyst type, a catalyst amount, a catalyst form, a dilution method for the catalyst, and lengths of reaction zones.

9. The method for vapor phase catalytic oxidation according to claim 1 , wherein the method further comprises:

packing the catalyst by allowing the catalyst to fall using a funnel with a net in at least a part of the funnel, for packing the catalyst in the reaction tubes.

10. The method for vapor phase catalytic oxidation according to claim 1 , wherein the method further comprises:

interposing a chain substance inside the reaction tubes so that a lower end of the chain substance is positioned above an upper end of a catalyst layer; and

packing the catalyst by allowing the catalyst to fall, for packing the catalyst in the reaction tubes.

11. A production method for (meth)acrolein or (meth)acrylic acid wherein the method comprises:

using the method for vapor phase catalytic oxidation according to claim 1 ; and

oxidizing propane, propylene, or isobutylene using molecular oxygen to produce (meth)acrolein or (meth)acrylic acid.