RU99126282A - METHOD FOR PROCESSING CONCENTRATED SULFUR GAS - Google Patents

Claims (2)

1. A method of processing concentrated sulfur dioxide gas into sulfur trioxide according to a cyclic scheme, comprising the steps of oxidizing sulfur dioxide in a multilayer contact apparatus by distributing the initial sulfur dioxide gas between the layers of the contact mass, dividing the contact gas from the output of the layers into streams, separating sulfur trioxide from the contact gas, and blowing from recycling of the part of the exhaust gas, previously purified from sulfur oxides returned to processing, characterized in that the process of oxidation of sulfur dioxide into a multilayer contact ohm apparatus is performed by a series-parallel circuit by means of flow distribution source of sulfur dioxide and oxygen W V over the layers of the contact apparatus, and dividing the contact gas stream Z _i from the output of each i-th layer for i = 1,2, ..., m, where m is the number of layers to flows X _i and Y _i supplied: stream X _i to the input of the next (i + 1) th layer, from the output of the last layer, stream X _{m is} returned to the input of the first layer, stream Y _i to the stage the release of sulfur trioxide, then into recycling, while the composition of the reaction gas, including the content of sulfur dioxide N _SO2нi , oxygen and N _O2нi , sulfur trioxide N _SO3нi , at the entrance to each i-th layer is supported, based on the joint fulfillment of the following conditions
T $\genfrac{}{}{0ex}{}{\text{k}}{\text{i}}$ - T $\genfrac{}{}{0ex}{}{\text{n}}{\text{i}}$ + Δl _i = T _pi - T _Зi (1)
T _zi ≤ T _i ^H <T _i ^K ≤ T _pi (2)
τ _pri = (1 + Δ2 _i ) • τ $\genfrac{}{}{0ex}{}{\text{0}}{\text{ci}}$ (3)
0≤Δ2 _i ≤0.5 (4)
the values of the values of W _i , V _i , X _i and Y _{i are} determined by the material balance of the layer, by the material balance of the process of dividing the stream Z _i from the output of the (i-1) th layer, and by the material balance of the process of mixing the flows W _i and Y _i , according to the following equations:
X _il = Z _il • N _SO3нi / N _SO3ki-l (5)
At _i-1 = Z _i-1 - X _i-1 (6)
W _i = N _SO2нi + N $\genfrac{}{}{0ex}{}{\text{w}}{\text{02i}}$ - N _SO2ki-l • X _il / Z _il (7)
V _i = N _O2нi - N $\genfrac{}{}{0ex}{}{\text{w}}{\text{02i}}$ - N _O2ki-l • X _il / Z _il (8)
moreover
W _i + V _i + X _il = N _SO2нi + N _O2нi + N _SO3нi (9)
ΣW _i = W (10)
ΣV _i = V (11)
W _i = N $\genfrac{}{}{0ex}{}{\text{w}}{\text{SO2i}}$ + N $\genfrac{}{}{0ex}{}{\text{w}}{\text{O2i}}$ (12)
V _i = N $\genfrac{}{}{0ex}{}{\text{v}}{\text{O2i}}$ (thirteen)
where T _i ^H , T _i ^K is the temperature of the reaction gas at the inlet and outlet of the i-th layer of the contact mass, K; T _s , T _p - temperature, respectively, of ignition and the beginning of thermal destruction of the contact mass of the i-th layer, K; Δl _i - stock, thermal stability of the contact mass, K; Δ2 _i is the dimensionless margin taking into account the decrease in the activity of the contact mass of the layer; τ _pri is the residence time of the reaction gas in the i-th layer of the contact mass, s; τ _ci is the theoretical contact time of the reaction gas with the surface of the contact mass of the i-th layer, s; τ $\genfrac{}{}{0ex}{}{\text{0}}{\text{ci}}$ - theoretical contact time with the surface of the contact mass of the i-th layer for the volume of the reaction gas without sulfur trioxide at the inlet of the layer and with the ratio of the number of moles of sulfur dioxide to the number of moles of oxygen, s, as for τ _ci ; W _i - distributed in the i-th layer stream of the source of concentrated sulfur dioxide gas, mol / s; N $\genfrac{}{}{0ex}{}{\text{w}}{\text{SO2i}}$ , N $\genfrac{}{}{0ex}{}{\text{w}}{\text{O2i}}$ - the content of sulfur dioxide and oxygen in the stream W _i mol / s; V _i - oxygen flow distributed in the i-th layer, mol / s; N $\genfrac{}{}{0ex}{}{\text{v}}{\text{O2i-l}}$ - the oxygen content in the stream V _i mol / s; Z _i-1 — contact gas flow leaving the (i-1) th layer, mol / s; N _SO2ki-l , N _O2ki-l , N _SO3ki-l - content of SO ₂ , O ₂ , SO ₃ in the stream Z _i-1 , mol / s; X _i-1 , Y _i-1 - flows arising from the division of the flow Z _i-1 , mol / s. 2. The method according to p. 1, characterized in that at the stage of oxidation of sulfur dioxide use technical or technological oxygen or an oxygen-air mixture
V _i = N $\genfrac{}{}{0ex}{}{\text{v}}{\text{O2i}}$ + N $\genfrac{}{}{0ex}{}{\text{v}}{\text{N2i}}$ (14)
where N $\genfrac{}{}{0ex}{}{\text{v}}{\text{N2i}}$ - nitrogen content in the stream V _i , mol / s.