THE INFLUENCE OF STARTING AND SUPPORTING BOILERS ON STEAM DISTRIBUTION SYSTEM AT AMMONIA SYNTHESIS WORKSHOP AM76 TYPE

A. V. Ivanchenko, O. V. Pass

Abstract


Ammonia inUkraineis produce on multi-tonnage aggregates AM76 type. Consumption of resources and energy at Ukrainian factories is much more than at modern world factories. As raw material prices increase, the price of ammonia without optimization of technology and modernization of productions is significantly increasing too.

The cost of natural gas is about 90% of ammonia prime cost. Natural gas is used in methane conversion and for supply the plant with steam. The steam is needed for the conversion reaction and driving turbines of main compressors. The issue of improving production to reduce natural gas consumption is relevant because of its high cost and consumption.

The authors of the article suggest simultaneously operating of starting and supporting boilers (for medium and high pressure steam production). And using of manual control of gas-serving to the starting boiler in order to stop undesirable oscillations in the high-pressure steam system.

During the experiment it was found that starting and supporting boilers interact in such a way that increasing load of starting boiler by gas leads to the next processes: increase of steam pressure in the medium pressure collector; the control system of the synthesis-gas compressor reduces the selection of partially used steam; decrease of pressure in the steam barrel, that is registrated by the gas feed valve for the burners of the supporting boiler; valve begins to close reducing gas consumption.

As a result of unloading the boiler and reducing of steam consumption from the steambarrel, the temperature of superheated steam decreases and then gas feeding valve of superheater closes to reduce gas consumption. Moreover, reducing of the gas consumption by supporting boiler leads to deeper depression in the boiler furnace and primary-reforming reactor, which allows reducing both speeds of the smoke exhaust turbines and consumption of the steam.

It has been determined, that increase of  gas load at starting boiler of 100 m³/h decline gas consumption by supporting boiler of 140-150 m³/h and 35-40 m³/h by steam superheater  (at ambient temperature of 18°C and at full load on the primary reforming reactor).

Also, it has been revealed, that desirable to set the load of the starting boiler so that the steam pressure is about 43 kg/cm² at operating work of both boilers without going beyond the rules, because it is economically feasible. Optimal load distribution for starting and suppor-ting boilers is 2700 m³/h and 3970 m³/h respectively (at ambient temperature of 18°C). Gas economy under such values is equivalent 215,35 tons of liquid ammonia per month, in comparison with using boilers at pressure 38 kg/cm².


Keywords


ammonia; AM76; starting boiler; supporting boiler; control system of the synthesis-gas compressor

References


Кузнецов Л.Д. Синтез аммиака / Л.Д.Кузнецов. – М.: «Химия», 1982. – 296с.

Янковский Н.А. Аммиак. Вопросы технологии / Н.А.Янковский. – Д.: «Новая печать», 2001. – 122с.

Дирявка А.Г. Инструкция по рабочему месту аппаратчика конверсии 6 разряда / А.Г.Дирявка. – Каменское: ЧАО «ДНЕПРАЗОТ», 2017. – 173с.




DOI: https://doi.org/10.31319/2519-2884.33.2018.204

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Copyright (c) 2019 A. V. Ivanchenko, O. V. Pass

ISSN (print) 2519-2884

ISSN (online) 2617-8389