what is the source of debris inside the pipeline

The chmical composition of the debris is first requisite to know to the source of the debris such as reaction product with the material of the pipelines, gas compositoin, idle time of the gas flow, trapped-humidity, gas composition, corrosive nature of the debris, etc.to narrow down the procedures to minimize.The biomass and corrosion/rust (assuming gas pipelines are from Carbon steel/API grade) can be the compositional ingradients. More the detail, easier the excercise to minimize the volume of the debris.

yes,

BUT: debris formation is typically a result of a chemical reaction between the transported fluid and the pipe alloy,

I want some of these reactions formulas if the fluid inside the pipeline was gas (any type of gas)

and how can we manipulate these formulas to reduce debris

the steps for a surface reaction can vary depending on the compounds and substrate used. However, for any chemical reaction the procedure is to derive a given mechanism and solve it for all measurable quantities and then match this with experimental data. if it doesn't match a different mechanism is assumed and the process is repeated. Some changes to the mechanism include switching the rate limiting step or even introducing other intermediate reactions.

A handy book to check out is "Elements of Chemical Reaction Engineering" by H. Scott Fogler. Chapter 10 pertains to chemical/surface reactions.

If you are keeping the required information away from the persons, who are there to help you out, how can you expect the solution of the problem ? Are you shying away from a medical professional, in sharing your problems, if you want to get back to the healthy state? The Informations needed are basic in nature and it has to be made available.

As you are aware and is stated in the other posts, any chemical reaction products are a function of the gas analysis and the materials of construction of the piping. Therefore a complete analysis of the gas is in order, as well as a knowledge of the materials used in the pipeline. Additionally, I would look at the temperture and pressure conditions to which the gas comes in contact at and near the location of the pluggage.

I have seen coke oven gas piping totally plug from ferrous thiocyanate crystals due to high humidity in the gas causing partial condensation of the moisture. This can occur, e.g. in winter, when piping is cold (if unlagged). The condensation will allow HCN to dissolve in the water and react with iron in piping.

I guess I'm saying a complete analysis of the conditions may be necessary to solve the problem.

If this debris is the product of a chemical reaction and the materials of construction of the pipeline, then the pipeline material specification is incorrect. Change the pipeline for a different material otherwise there will be either a containment problem or a structural failure in time. Your insurance company may take a dim view if you don't...

http://www.coleparmer.com/techinfo/chemcomp.asp