CQIM을 이용한 유연탄과 무연탄의 연소성 및 경제성 평가

김성철, 김태형, 김영주

전력연구원 발전연구실

Evaluation of Combustion Characteristics of Bituminous Coal and Anthracite

Using Coal Quality Impact Model

Sung-Chul Kim,  Tai-Hyeung Kim, Young-Zoo Kim

Power Generation Laboratory

Korea Electric Power Research Institute

INTRODUCTION

The CQIM is capable of predicting cost and performance impacts of switching coals in existing pulverized coal power generating units. Detail equipment models are determined unit and system performance, auxiliary power, consumables, waste generation, derates, replacement power, and maintenance costs. The program includes  detailed heat transfer model of steam generator and detailed maintenance/availability model.

Developing a typical CQIM analysis can be viewed as constructing a project by pointing to information stored in various files. A project file is made up of data found in the following four types of files.

Project file are tied with the other files together to form a project to be submitted to the calculational program for processing. It also contains all the data, such as economic data, common to each unit being analyzed.

Unit files contain all the data on the units being modeled. These include all equipment dimensions, power requirements, configurational data, performance data, and operating parameters. Up to four different units may be modeled in a project.

Fuel file contains all the fuel quality data for up to 50 fuels to be analyzed for all the units in the project. Maintenance/Availability file contain historical costs for material, mean time between failures, and time-to repair data on an individual component basis.

MODELING

Design data and performance test data of Samchonpo thermal power plant unit #3, 4 is entered for CQIM unit file. Excess air ratio is 3.26% at exit of furnace. Air heater leakage is 8.39% and exit flue gas temperature is 130□. Availability is 83% and coal fineness is 75% which is passing the 200 mesh.

Evaluation coals are KIDECO, CNCIEC, COALEX and korean anthracite. Blending ratio of KIDECO, Subbituminous coal, is not exceed 40%, so Blending ratio of KIDECO is fixed up to 30% in this modeling. Korean anthracite blending ratio is fixed to 10%, 29%, 30% .  These coals are analyzed and the results are shown in Table 1.

RESULTS

Fig. 1 shows the availability of Samchonpo power plant with blending ratio for one year. Design availability is 83%. As anthracite blending ratio is increased, availability is decreased. In case of CNCIEC coal, availability is decreased by 0.3% when 30% anthracite coal is blended compared to CNCIEC itself firing and availability of 30% subbituminous coal KIDECO blended with CNCIEC is decreased by 0.4% compared to CNCIEC itself availability.

Table 1. Analysis of the test coal

Property		KIDECO	COALEX	CNCIEC	Anthracite
Proximate analysis (wt %)	Moist F.C V.M Ash	13.04 43.71 40.12 3.13	2.18 56.06 26.54 15.22	1.85 52.38 30.37 15.40	3.99 58.66 6.90 30.45
Ultimate analysis (wt %)	C H O N S Ash	70.32 4.69 30.14 1.19 0.06 3.60	71.09 3.86 7.47 1.54 0.37 15.67	76.03 3.95 2.90 1.30 0.13 15.69	61.22 0.78 1.18 0.41 0.41 36.00
Ash analysis (wt %)	SiO2 Al2O3 Fe2O3 CaO MgO Na2O K2O SO3	46.18 18.38 14.35 7.64 2.50 0.19 1.23 4.36	64.11 27.37 3.72 0.83 0.53 0.10 1.05 1.05	55.42 24.02 5.77 2.26 0.84 0.70 1.71 2.21	53.66 31.42 4.30 1.04 0.79 0.37 4.59 0.30
Calorific value(□/□) HGI IDT(□) Price(Won)		5,476 53 1,206 37,699	6,212 73 1,508 50,152	6,365 71 1,341 45,324	4,670 70 1,550 71,700

Fig. 1. Comparison of availability with blending ratio

Fig. 2 shows the SOx and NOx emission of outlet of electrostatic precipitator. Environmental regulation for Samchonpo power plant is 270ppm for SOx and 350ppm for NOx. 20% and 30% anthracite blended with COALEX and subbituminous coal blended with COALEX could not meet the SOx regulations. As increase of anthracite blending ratio, SOx emission is also increased It is owing to the anthracite has high sulfur content compared to other coal. NOx, Considering all cases, could meet the environmental regulation.

Fig. 2. SOx and NOx emission

Fig. 3 shows generation cost(included: coal related cost, maintenance cost and ash disposal cost).  Electric generation cost of CNCIEC itself is 16.28won/kWh and 30% blended with anthracite is 20.56won/kWh. Generation cost of Coalex is 18.23 won/kWh and 30% blended with anthracite is 22.21 won/kWh. 30% subbituminous coal blended with CNCIEC is 16.23 won/kWh and 30% subbituminous coal blended with COALEX is 17.49 won/kWh.

CONCLUSIONS

When anthracite is blended with bituminous and subbituminous coal in power plant, Many problem will be occurred such as decrease of availability, insufficient of pulverizer capacity, increase of dust and SOx emission, and erosion tendencies. Generation cost(included: coal related cost, maintenance cost,  ash disposal cost) of bituminous coal itself  is 17.03won/kWh and electric generation cost of 30% blended with anthracite is 21.28won/kWh on the mean average. So blended with 30% anthracite coal on Samchonpo thermal power plant, 17 billion won of additional cost per year will be needed under 83% availability.

As considering the economic aspects, it is impossible to use some amount of anthracite with bituminous or subbituminous coal on power plant.

Fig. 3. Electric generation cost

REFERENCE

1. CQIM theory manual, EPRI GS-7-16-CCML, 1990

2. CQIM user manual, EPRI CM-110502, 1998