and high-tech

Energy Efficiency. Benefits of Energy Saving

Power equipment

Energy saving is an important strategic and modern issue, the interest to which in the course of time only increases in all spheres of society in industrially developed countries.

The governments of most countries are concerned about dependence on imported energy resources, and as a result must carry out a whole range of specific measures to implement energy-saving policies in all industries.

The Resolution of the Cabinet of Ministers of the Republic of Uzbekistan No. 164 dated August 7, 2006 approved the "Rules for conducting energy audits and examinations of consumers of fuel and energy resources". The successful implementation of the Resolution requires the development of a research methodology that provides a more detailed study of the possibility of saving energy for fuel and energy consumers.

A consumer facing a growing energy price can reduce losses by using, for example, some types of insulation or by switching to cheaper fuel, and at the same time spending money on new equipment that is financially acceptable, to consider the schemes of technological processes, to analyze the main loss of heat, as well as electricity and ways to increase the efficiency of their use, considerable attention should be paid to the utilization of waste heat.

Today, the urgency of saving fuel and energy resources has increased, as the main component of the expenditure of the most energy-intensive industries is the cost of energy.

In developed countries, 50-60% of total energy consumption goes to the needs of the industrial sector. In the conditions of the world economic crisis, an important factor in the stability of the country's economy is the solution of fuel and energy problems. Recently, much attention is paid to the issues of fuel and energy saving, which are common for enterprises of various industries.

More than 50% of the total energy consumption in the industry falls on chemical and ferrous metallurgy enterprises. The rest of the energy consumption is roughly divided equally between energy-intensive industries (enterprises of non-ferrous metallurgy, building materials, pulp and paper, food industries) and non-energy-intensive industries (machine building, metalworking, radioelectronic, light, etc.).

The engineering company ENCE GmbH (Switzerland) has been actively working with chemical, metallurgical, gas processing enterprises for many years, specializing in the supply of equipment.

Based on many years of experience, ENCE GmbH is ready to offer you interesting engineering projects using advanced technologies in fuel and energy saving issues, which ultimately leads to a reduction in the cost of production, while increasing its competitive ability in the market.

Energy saving in metallurgy
Brief description of the calculation purpose

Our company carried out the modernization of the section mill at Uzmetkombinat. Within the framework of the project reconstruction of the furnace with walking beams of the section rolling shop No.2 was carried out. The implementation of the project will reduce energy consumption by 50% for heating steel billets and reduce emissions of harmful substances by almost 30%.

Estimation of the economic efficiency of the project on reconstruction of the walking beam reheating furnace at Uzmetkombinat proposed by ENCE GmbH is as follows:

Process parameter Before reconstruction After reconstruction
Natural Gas 76 m3/t 36 m3/t
Metal Production Output 645,3 kiloton 779,2 kiloton
Scale Loss 1,8% Max 0.8%
Metal quality improvement Reduction of quantity of “black patches” and as consequence a uniform temperature throughout the area of the billet
Lowering of labor contribution for the reconstruction The geometric dimensions of the furnace do not change. Former burners can be used again

Innovations in energy: effective changes to improve furnace performance

The most effective changes that should be made to improve the technical and economic performance of the furnace with the shortest payback period are the following:

  • Replacement of stationary and walking beams and support racks with new ones with optimal location to prevent excessive bending of the blooms, with effective refractory insulation of water-cooled pipes and hydraulic locks;
  • Installation of a new system for optimization of controlling the operation of the furnace, evaporative cooling system, heat-recovery boiler or recuperator;
  • Installation of a system for optimization of the temperature regime of the furnace;
  • Installation of a new system for automatic / manual setting of the billet position before loading into the furnace in accordance with the improved design diagram of billet loading;
  • Improved loading and unloading dampers;
  • Installation of a hydraulic system for lifting and walking cylinders of the walking beam mechanism.

The optimization system for heating furnaces has been designed to achieve maximum furnace capacity with minimal fuel consumption, as well as solving technological problems from loading into the furnace to loading into the section mill.

Scheme of the optimization system

Below is a description of the exchange of data and information signals exchanged between the system and other objects in levels 1,2,3. Data exchange is predominantly performed over the local ETHERNET / TCP-IP network. More intensive data exchange is established in the phase of functional analysis.

Energy saving in the chemical industry
Brief description of the calculation purpose

The first-stage methane conversion tube-type furnace is designed to heat the following process streams:

  • steam-gas mixture
  • steam-air mixture
  • boiler water
  • wet steam
  • deaerator feed water

The fuel used is natural gas, tank and purge gases. Ejector burners are used as gas burners. The temperature of the exhaust flue gases after the furnace is 240°C at a rate not exceeding 220°C. Exhaust gases are injected into the atmosphere by exhausters item 121А/В through a chimney item 122 (scheme No.1).

In order to reduce heat losses with outgoing gases and intensify heat transfer in the furnace, it is proposed to introduce the following changes into the furnace piping scheme (scheme No.2):

  • Install mixing gas burners with forced air supply
  • Install an air heater on the exhaust gas line to reduce the flue gas temperature to 120°C
  • Install blast air fans and air ducts to supply air from the fans through the air heater to the burner with forced air supply

The existing scheme of the burners piping and flue gases

The proposed scheme for the burners piping and flue gases

Calculation of natural gas saving when installing an air heater for the flue gas after the furnace

The loss of heat with outgoing flue gases after the furnace is determined by the formula:

Q = (VCO2·CCO2 + VH2O CH2O + VN2·CN2 + VO2·CO2)·tу.г., kcal/h

VCO2, VH2O, VN2, VO2 — volumetric flow of combustion products СО2, Н2О, N2,O2, m3/h;
CH2O, CN2, CO2 — average specific heat of combustion products СО2, Н2О, N2 и О2, kcal/m3;
tу.г. — flue gas temperature, °C. For tу.г. = 240°C;

Qу.г. = (27171·0,434 + 62833·0,366 + 253376·0,311 + 11158·0,321)·240 = 28121040 kcal/h ≈ 28,12 Gcal/h

Heat loss with exhaust flue gases after the air heater

For tу.г. = 120°C

Qу.г. BB = (27171·0,410 + 61833·0,361 + 253376·0,309 + 11158·0,316)·120 = 13877040 kcal/h ≈ 13,88 Gcal/h

Heat energy of flue gases directed to air heating in the air heater

QB = Qу.г. - Qу.г. BB = 28121040 -13877040 = 14244000 kcal/h ≈ 14,244 Gcal/h

Heat energy usefully used in the air heater

QПB = QB·K, kcal/h

К — air heater efficiency 0,9

QПB = 14244000·0,9 = 12819600 kcal/h ≈ 12,82 Gcal/h

The maximum air temperature tГB after the air heater is determined by the formula:

QBП — heat energy useful used in the air heater, kcal/h
VФ — actual air flow, m3/k
СB — average volume specific heat of air, kcal/m3
tН — outside air temperature 30°C

Natural gas savings per hour is determined by the formula:

The annual savings of natural gas will be: 1563,4·24·330 = 12382128 m3/h