2.6. Reconstruction of NIISTU-5 boilers in order to increase the efficiency of natural gas combustion

Substance of problem

The essence of the problem: about 35 thousand NIISTU-5 boilers are operated in Ukraine, the heating capacity of which does not exceed 0.6 Gcal/h, and the efficiency is 75-80 %. The proposed development provides, through the reconstruction of NIISTU-5 boilers, an increase in their thermal capacity and efficiency. The cost of reconstruction of such inefficient boilers is 3-4 times lower than replacing them with new ones.

Description of technology

Reconstruction of NIISTU-5 boilers is carried out by introducing new design elements, namely: additional convective heating surfaces and new upgraded slot burners (with or without radiators).

There are three options for the reconstruction of boilers:

  • installation of single-row additional convective heating surfaces and slot burners without emitters.This provides an increase in efficiency by 10-12 %;
  • installation of double-row additional convective heating surfaces and slot burners without emitters. Provides an increase in efficiency and an increase in thermal power by 60-70 %;
  • the introduction of slit burners with emitters provides an increase in efficiency by 4-5 %.
The economic effect of the conversion of boilers

Number of converted boilers

Savings from increased efficiency, thousand UAH in year

Savings from increased efficiency and heat production, thousand UAH in year

1

10,8

18,86

2

21,6

37,71

10

135,0

215,23

50

702,0

1103,98

100

1411,4

2211,83

1000

14168,3

22198,91

When reconstructing one boiler of the NIISTU-5 type, with a heating capacity of 0.585 Gcal / h and an efficiency of 80 % with an increase in heating capacity of up to 1 Gcal / h and an efficiency of 91.34 % (option A), or with an increase in efficiency of up to 90 % without increasing heat output (option B) such indicators are achieved.

Indicators Option A Option B
Gas saving, m³/year 46177  23969
Reducing the amount of harmful gaseous emissions:    
     – Nitrogen oxides, kg/year 96,82 50,3
     – Carbon oxides, kg/year 91,88 47,7
     – Carbon dioxide kg/year 90224 46832